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Valve Clearance Question XJ650

Discussion in 'XJ Technical Chat' started by jctp124, Oct 5, 2023.

  1. jctp124

    jctp124 New Member

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    Had a question about valve clearance that I couldn't find.

    Here are my measurements as a preface:

    I1 - .10mm
    I2 - .10mm
    I3 - .12mm
    I4 - .13mm

    E1 - .13mm
    E2 - .16mm
    E3 - .17mm
    E4 - .15mm


    I checked each one three times, and on some got two different measurements. I am bad at judging when things are straight, so is it possible on some of them I didn't have the lobe exactly opposite of the shim? Maybe off by 10 degrees give or take?

    For example, intake one first measured at .06mm, when I came back to it to recheck, it measured .10mm.

    Another question is: thing happened with exhaust 2 and 3, both were initially measured at .18mm, but couldn't move the feeler gauge all the way across the shim, so reduced the gauge size until I could move it all the way across the bottom of the heel of the lobe. I figured clearance is clearance in this case. That right?
     
    jctp124, Oct 5, 2023
    #1
  2. Huntchuks

    Huntchuks Well-Known Member

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    The manuals say to turn the crank to (piston) top dead center mark, which is not the same as the cam lobe facing directly away from shim face by 90 degrees. Lot's of people just do the 90 degrees though. The way the cams are ground, I'm not sure if it makes a difference. I follow the manual.
     
    Huntchuks, Oct 5, 2023
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  3. cds1984

    cds1984 Well-Known Member

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    Yes, clearance is clearance.
    If you move the cam and get a greater clearance you are on the money.

    The clearance is based on having clearance as with wear on the valve or valve seal it reduces and the valve ends up remaining open, because the shim and cam aren't degrading to súit, in the worst case scenario.

    You never want to go under the tolerance but up to the tolerance is good.
     
    cds1984, Oct 7, 2023
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